AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeP

Paper TF-WeP24
A Study of the Growth Front of Au Policristalline Films and its Relation with the Bulk Structure of the Films

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: J.L. Sacedon, CSIC, Spain
Authors: C. Munuera, CSIC, Spain
J.A. Aznarez, CSIC, Spain
E. Rodriguez, CSIC, Spain
A.I. Oliva, Centro de Investigaciones y Estudios Avanzados del IPN Unidad de Merida, Mexico
M.A. Aguilar, CSIC, Spain
J.L. Sacedon, CSIC, Spain
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The surface roughness of Au polycrystalline films with a high (111) texture has been studied using STM images. The growth front has been characterized in samples with thickness from 30 to 1800 nm by measuring the interface width and the coarsening of apparent rounded mounds. In this analysis any isotropic or self-affine hypothesis has been avoided. In addition, the fracture of the thickest films have been analysed by SEM. The films have been obtained by thermal evaporation on native SiO@sub 2@ terminated Si(100) substrates maintained at room temperature. The rate of growth was 1.0 nm/s. The SEM images show a competitive columnar growth for thicknesses from <90nm to 1800 nm. They also show that the mound round shaped structures correspond to the top of the columns. The interface width scaling behaviour obtained from STM images shows two growth regimes, the more advanced starts at 60 nm and corresponds to a constant morphological slope regime.In this advanced stage, the value of the interface width and coarsening scaling exponents are close to 1/3. The exponent values and fracture structures agree with the parametric model of E.V. Albano et al.(PRB 59,7354 (1999)). This model is based on the concept that surface diffusion phenomena controls the bulk structure of the film. Local slopes along the surface profiles are compatible with a significant step down atomic current component, which is necessary to allow the burial of the less competitive columns. The linear boundaries of the surface structure suggest a relaxation of the columnar boundaries to crystalline planes causing the weak hexagonal symmetry observed in the height to height correlation functions.